Preoperative dual-energy CT colonography has been found to be an accurate and dose-efficient primary staging examination for colorectal cancer, which ranks second in women and third in men for most commonly diagnosed cancers in developed countries.

In a study recently published in Academic Radiology, Benno Schaeffer, MD, of the University of Munich, and a team of researchers evaluated the benefits of dual-energy CT colonography as a staging examination. The team scanned 22 patients known to have abnormal colorectal growths. These patients underwent a preoperative abdominal dual-energy CT colonography and those scans were evaluated by two radiologists for local tumor stage and the presence of synchronous intracolonic and extracolonic findings.

Twenty-two carcinomas were revealed using the dual-energy CT technology, including 19 adenomas. Accurate preoperative staging was achieved for all patients in the study.

“Full preoperative colonic assessment is important as synchronous intracolonic lesions are frequently encountered and were seen in 50 percent of our study population,” Schaeffer and colleagues wrote. “If a synchronous cancer or adenoma remains undetected at initial staging, morbidity and mortality associated with a second operation will increase”

Researchers found an additional benefit to preoperative dual-energy CT staging. As a result of the procedure, providers were able to visualize and quantify iodine uptake, underlining that dual-energy CT staging enables reliable discrimination of enhancing colonic neoplasia from benign structures which will not show significant enhancement.

On the other hand, the ability of single-energy CT colonography to discriminate carcinomas from noncancerous lesions nearby to the stenosing colorectal cancer is limited.

“Our results show that [CT colonography] performed in a [dual-energy] mode cannot discriminate adenomas from carcinomas as they enhance similarly,” the researchers wrote.

Additionally, the research team was able to determine that dual-energy CT colonography performed in a single position, supine, was sufficient in providing a thorough evaluation of colonic neoplasia patients.

“Without need for prone scanning, acquisition time, examination costs, and patient discomfort can be reduced,” Schaeffer and colleagues wrote.